The photo of a frumpy man in a cardigan pretty much sums up “Derek,” Ricky Gervais’ newest series premiering Sept. 12 on Netflix.

While I’m a big fan of his previous TV work — most notably “The Office” (brilliant) and “Extras” (not far behind) — Gervais whiffs here with a cringe-worthy, borderline-insulting performance.

As a whole, “Derek” — shot in fly-on-the-wall documentary style a la “The Office” — has its moments, and is often quite touching. So kudos to series writer/creator /director Gervais for that.

But it’s brought crashing to an embarrassing standstill whenever his Derek Noakes, a 50-year-old, childish, possibly autistic worker at an assisted living facility, appears on-screen. Gervais’ take on Derek reminds me of Jerry Lewis, not only because Derek is a horribly stereotypical character — aka Lewis’ buck-toothed, coke-bottle-glasses-wearing Japanese chef in the 1980 bomb “Hardly Working” — but because Gervais seems to have transferred a chunk of his personal reality to his fictional alter-ego.

Some armchair-psychologists have theorized that Lewis hosted his MDA telethons all those years because — deep in the bowels of his subconscious — he was atoning for some of his on-screen characters, who might be interpreted as being mentally challenged. Hey lady!

A few years back, Gervais — known to poke fun at the handicapped in his stand-up routine — found himself in hot water for referring to “Britain’s Got Talent” winner Susan Boyle with an offensive, anachronistic British term describing Down’s Syndrome. He then defiantly repeated the term to his Twitter followers and tweeted a photo of himself making a contorted face. ’Nuf said.

Now he’s given us his perception of a “simple,” angelic man-child. Derek wears his greasy hair combed straight down like Moe Howard, his ill-fitting pants hiked way up and his buttoned-to-the-throat shirt covered by a ratty sweater.

He also has a strange mouth tic, which I think is supposed to telegraph his empathy but only reminded me of the simpleton character Andy Millman (Gervais) played in his “Extras” sitcom-within-a-sitcom, “When the Whistle Blows.”

While the supporting cast here is very good — particularly Gervais regular Karl Pilkington (“An Idiot Abroad”) as angry handyman Dougie and Kerry Godliman as the empathetic facility manager, Hannah — Gervais tramples on everything by telegraphing emotional scenes with that trite standby, melancholy piano-music. He also has the characters playing too much to the (pseudo-documentary) cameras.

It was effective in “The Office”; here it’s just repetitive and annoying.